325 Spring Street (New York, NY) Sublease - 325 Spring Street LLC and ImClone Systems Inc.


                                    SUBLEASE

         AGREEMENT OF SUBLEASE ("Sublease") dated as of the 5th day of October,
2001, by and between 325 SPRING STREET LLC, a Delaware limited liability company
having an office c/o Savanna Partners, 80 Fifth Avenue, New York, New York
("Sublandlord"), and IMCLONE SYSTEMS INCORPORATED, a Delaware corporation having
an office at 180 Varick Street, New York, New York ("Subtenant").

                                    WHEREAS:

         I. By lease agreement dated as of May 8, 2000 between United Parcel
Service, Inc. ("Overlandlord"), as landlord, and SenseNet, Inc., as tenant, as
amended by (a) First Amendment to Lease Agreement (the "First Amendment"), dated
as of November 1, 2000 and (b) Second Amendment to Lease Agreement, dated as of
October 4, 2001 (as amended, the "Overlease"), SenseNet leased from Overlandlord
certain premises in the building (the "Building") known as 325 Spring Street,
New York, New York; and

         II. By Assignment and Assumption of Lease, dated as of November, 2000,
SenseNet assigned to Sublandlord, and Sublandlord assumed from SenseNet, all of
SenseNet's right, title, obligations and interest in and to the Overlease; and

         III. Subtenant desires to sublet from Sublandlord the portion of the
premises demised to Sublandlord under the Overlease more particularly described
on Exhibit A annexed hereto (the "Sublease Premises"), upon the terms and
subject to the provisions and conditions hereinafter set forth.

         NOW, THEREFORE, the parties hereto, in consideration of the mutual
covenants, conditions and agreements hereinafter contained, do hereby agree as
follows

                                  WITNESSETH:

         1. Term. Sublandlord hereby sublets the Sublease Premises to Subtenant,
and Subtenant hereby hires the Sublease Premises from Sublandlord, for a term
(the "Term") which shall commence on the later to occur of (a) October 5, 2001
and (b) two (2) business days after the date upon which a copy of the consent,
executed by Overlandlord, whereby Overlandlord grants its consent to this
Sublease in accordance with Article 21 herein is delivered to Subtenant (the
"Commencement Date"), and which shall end on April 29, 2023 (the "Expiration
Date"), unless sooner terminated in accordance with the provisions of this
Sublease.

         2.       Annual Fixed Rent and Additional Rent.

                  A. Subtenant covenants and agrees that, during and throughout
the entire Term, Subtenant shall pay to Sublandlord annual fixed rent ("FIXED
RENT") in the amounts more particularly set forth on SCHEDULE 1 annexed hereto
and made a part hereof, during and for the period commencing on the Commencement
Date and continuing through and including the Expiration Date; which Subtenant
covenants and agrees to pay to Sublandlord, in lawful money of the United
States, in equal monthly installments in advance, on the fifth (5th) business
day prior to the first day of each calendar month during the Term, without
demand, deduction, offset, abatement, defense, and/or counterclaim whatsoever,
except that Subtenant shall pay the first monthly installment of Fixed Rent
simultaneously with the execution and delivery of this Sublease. The monthly
installment of Fixed Rent payable on account of any partial calendar month
during the Term shall be prorated. Notwithstanding anything to the contrary
contained herein, in the event (a) Sublandlord files a voluntary petition under
the United States Bankruptcy Code (or any other federal or state bankruptcy or
insolvency law) (the "CODE"), or (b) any direct or indirect member, shareholder,
partner, principal, affiliate, employee, officer, director, agent or
representative of Sublandlord (each, a "RELATED PARTY") commences, files,
solicits, participates in or joins in the filing of, an involuntary petition
against Sublandlord under the Code, or (c) Sublandlord files an answer
consenting to or acquiescing in (actual as distinguished from implied or
constructive consent) any involuntary petition filed it by any other person
under the Code, then the Fixed Rent from and after the date of such filing
(until such bankruptcy is discharged provided this Sublease is not as a result
of such bankruptcy, rejected, modified or terminated) shall be an amount equal
to the Base Rent payable by Sublandlord to Overlandlord under the Overlease.
Upon the occurrence of any of the events set forth in clauses (a), (b) or (c) of
the immediately preceding sentence (and until such bankruptcy is discharged,
provided this Sublease is not as a result of such bankruptcy, rejected, modified
or terminated), Subtenant may pay the Base Rent payable by Sublandlord to
Overlandlord under the Overlease, directly to Overlandlord.

                  B. In addition to the Fixed Rent payable hereunder, Subtenant
shall be liable for, and shall pay to Sublandlord on or before the date which is
five (5) business days prior to the date upon which any and all such amounts are
payable by Sublandlord to Overlandlord pursuant to Sections 3(b) and 3(h) of the
Overlease, 95.1% of any and all amounts payable by Sublandlord to Overlandlord
pursuant to Sections 3(b) and 3(h) of the Overlease.

                  C. All payments of Fixed Rent and additional rent (Fixed Rent
and additional rent are collectively referred to herein as "rent" and all sums
as shall become due and payable by Subtenant to Sublandlord pursuant to this
Sublease other than Fixed Rent shall be deemed to be "additional rent") shall be
made by good and sufficient check (subject to collection) currently dated, drawn
on a bank which is a member of the New York Clearing House or any successor
thereto, issued directly from Subtenant, without endorsements, to the order of
Sublandlord (or such other party as Sublandlord may, from time to time, direct)
at Sublandlord's office (or such other place as Sublandlord may designate from
time to time) Contemporaneously herewith, Sublandlord, Subtenant and Bank of
America Securities, L.L.C. (together


                                       2

with any successor thereto, the "LOCK BOX BANK") are entering into a lock-box
arrangement. Notwithstanding the provisions of this sub-paragraph C, from and
after November 1, 2001, and for so long as such arrangement is in effect,
Sublandlord and Subtenant agree that all rent shall be paid to and disbursed by
the Lock Box Bank in accordance with the terms of such lock-box arrangement;
provided, however, that the foregoing shall not in any way limit Subtenant's
obligations hereunder for the payment of rent and additional rent, and Subtenant
acknowledges and agrees that the rent and additional rent payable by Subtenant
under this Sublease shall not be deemed to have been paid by Subtenant unless
and until disbursed and received in accordance with the lock-box arrangement.

                  D. In the event that additional rent is due under the
Overlease with respect to any period which precedes the Commencement Date or
follows the Expiration Date, Subtenant's obligations hereunder on account of
such additional rent shall be appropriately prorated.

                  E. Sublandlord shall have the same rights and remedies in the
event of nonpayment of additional rent as are available to Sublandlord for the
non-payment of Fixed Rent.

         3. Use of the Sublease Premises. Subtenant shall use and occupy the
Sublease Premises for (i) general and executive offices and/or (ii) a
biotechnology laboratory and incidental uses thereto, including, but not limited
to, laboratories for molecular biology, organic chemistry, tissue culture and
immunology (with appropriate drainage and ventilation), in accordance with the
terms and conditions of the Overlease (the "PERMITTED USE"), and for no other
purpose, and further covenants not to do any act which will result in a
violation of the Overlease.

         4. Incorporation of Overlease Terms.

                  A. All capitalized and other terms not otherwise defined
herein shall have the meanings ascribed to them in the Overlease, unless the
context clearly requires otherwise.

                  B. Except as herein otherwise expressly provided, all of the
terms, provisions, covenants and conditions contained in the Overlease are
hereby made a part hereof. The rights and obligations contained in the Overlease
are, during the term of this subletting, hereby imposed upon the respective
parties hereto, Sublandlord as being substituted for Overlandlord, and Subtenant
being substituted for Sublandlord with respect to the Overlease; provided,
however, that Sublandlord shall not be liable to Subtenant for any failure in
performance resulting from the failure in performance by Overlandlord under the
Overlease of the corresponding covenant of the Overlease, except to the extent
such failure is due to the negligence or willful misconduct of Sublandlord, and
Sublandlord's obligations hereunder are accordingly conditional where such
obligations require such parallel performance by Overlandlord. It is expressly
agreed that Sublandlord shall not be obligated to perform any obligation which
is the obligation of Overlandlord under the Overlease. Sublandlord shall have


                                       3

no liability to Subtenant by reason of the default of Overlandlord under the
Overlease. Subtenant recognizes that Sublandlord is not in a position and shall
not be required to render any of the services or utilities, to make repairs,
replacements, restorations, alterations or improvements or to perform any of the
obligations required of Overlandlord by the terms of the Overlease.
Notwithstanding anything contained herein to the contrary, Sublandlord agrees,
however, to use reasonable efforts to enforce its rights against Overlandlord
under the Overlease for the benefit of Subtenant upon Subtenant's written
request therefor (and to forward to Overlandlord any notices or requests for
consent as Subtenant may reasonably request). Upon presentation of reasonable
back-up of such costs, Subtenant shall promptly reimburse Sublandlord for any
and all costs which Sublandlord shall incur in expending such efforts, and
Subtenant does hereby indemnify and agree to hold Sublandlord harmless from and
against any and all claims, liabilities, damages, costs and expenses (including,
without limitation, reasonable attorney's fees and disbursements) incurred by
Sublandlord in expending such efforts. Nothing contained in this Subparagraph B
shall require Sublandlord to institute any suit or action to enforce any such
rights. Notwithstanding the foregoing, Sublandlord shall permit Subtenant to (a)
bring an action, in the name of Sublandlord and at Subtenant's sole cost and
expense, to enforce Overlandlord's obligations under the Overlease and/or (b)
provide notices (as the agent of Sublandlord) to Overlandlord to enforce
Sublandlord's rights against Overlandlord under the Overlease (to the extent
Sublandlord does not wish to do so or Sublandlord fails to do so after notice
from Subtenant and reasonable opportunity to respond, taking into account the
nature of the notice or if Sublandlord is in default hereunder beyond the
expiration of applicable notice and cure periods; except that in the case of the
First Extension Notice and the Second Extension Notice only, provided there does
not exist a default by Subtenant under this Sublease beyond the expiration of
applicable notice and cure periods, Subtenant may deliver such First Extension
Notice and/or Second Extension Notice, as the case may be, directly to
Overlandlord (as agent for Sublandlord) without first requesting that
Sublandlord deliver such extension notices to Overlandlord); provided that
Subtenant shall, and hereby does, indemnify Sublandlord against, and hold
Sublandlord harmless from, any loss, cost, damage, liability and expense
(including, without limitation, reasonable attorneys fees) which may arise in
connection therewith, except if arising from the negligence or willful
misconduct of Sublandlord. Subtenant acknowledges that the failure of
Overlandlord to provide any services or comply with any obligations under the
Overlease shall not entitle Subtenant to any abatement or reduction in rent
payable hereunder except to the extent (a) resulting from Sublandlord's
negligence or willful misconduct or (b) on a pro-rata basis, of any
corresponding abatement as a result thereof received by Sublandlord from
Overlandlord.

                  C. Wherever the Overlease refers to the "Premises," such
references for the purposes hereof shall be deemed to refer to the Sublease
Premises.

                  D. Sublandlord represents that to the best knowledge of
Sublandlord, as of the date hereof the Overlease annexed hereto as EXHIBIT "B"
and made a part hereof is a true and complete copy of the Overlease (and all
amendments and modifications thereto), except as to certain intentionally
omitted provisions, which provisions are expressly not incorporated herein and
made inapplicable to Subtenant and the Sublease Premises.


                                       4

         5. Sublease Subject to Overlease.

                  A. This Sublease is expressly made subject and subordinate to
all of the terms and conditions of the Overlease and to all matters to which the
foregoing is subject, except as specifically provided to the contrary in this
Sublease. Subtenant hereby assumes and covenants that, throughout the Term,
Subtenant shall observe and perform, all of the provisions of the Overlease
which are to be observed and performed by the tenant thereunder with respect to
the Sublease Premises. Subtenant covenants that Subtenant shall not do any act,
matter or thing which will be, result in, or constitute a violation or breach of
or a default under the Overlease; it being expressly agreed to by Subtenant that
any such violation, breach or default shall constitute a material breach by
Subtenant of a substantial obligation under this Sublease. Subtenant hereby
agrees that Subtenant shall indemnify and hold Sublandlord harmless from and
against all claims, liabilities, penalties and expenses, including, without
limitation, attorneys' fees and disbursements, arising from or in connection
with any default by Subtenant in Subtenant's performance of those terms,
covenants and conditions of this Sublease and/or of the Overlease which are or
shall be applicable to Subtenant, and all amounts payable by Subtenant to
Sublandlord on account of such indemnity shall be deemed to be additional rent
hereunder and shall be payable upon demand. In any case where the consent or
approval of Overlandlord shall be required pursuant to the Overlease or
otherwise, Overlandlord's and Sublandlord's consent shall be required hereunder
(except in respect of Article 6 of the Overlease and Article 9 of the Sublease
it being agreed to by Sublandlord that Sublandlord shall not deny consent to any
request made pursuant to the provisions thereof which is consented to by
Overlandlord), and Sublandlord shall have no obligation to consent to any matter
to which Overlandlord's consent is so required but not obtained.

                  B. Subtenant covenants and agrees that if, by reason of a
default on the part of Sublandlord, as the tenant under the Overlease, in the
performance of any of the terms or provisions of the Overlease, or for any other
reason of any nature whatsoever, such lease or the leasehold estate of the
tenant thereunder, is terminated by summary dispossess proceeding or otherwise,
then Subtenant will, at Overlandlord's election, attorn to Overlandlord, and
will recognize Overlandlord as Subtenant's landlord under this Sublease.
Subtenant covenants and agrees to execute and deliver, at any time and from time
to time, within five (5) days following a request therefor by Sublandlord or
Overlandlord, any instrument which may be reasonably necessary or appropriate to
evidence such attornment.

                  C. Subtenant agrees to be bound, for all purposes of this
Sublease, by any modifications or amendments to the Overlease. Sublandlord
agrees not to amend or modify the Overlease in any way that would discriminate
against Subtenant, or which would increase Subtenant's monetary obligations
hereunder, shorten the term hereof or decrease Subtenant's rights with respect
to the Permitted Use of the Sublease Premises, or which would otherwise
materially adversely affect Subtenant's rights or obligations hereunder or
permit the same to be canceled or terminated, unless required pursuant to the
terms of the Overlease, without Subtenant's prior written consent, provided,
however, that Sublandlord shall have the right to terminate this Sublease in the
event that Overlandlord terminates the Overlease in


                                       5

accordance with the provisions of Article 10 of the Overlease (provided, that,
Sublandlord shall promptly deliver to Subtenant any notice received by
Sublandlord from Overlandlord pursuant to Article l0 of the Overlease and if,
upon receipt by Subtenant of such notice there exits no default by Subtenant
beyond the expiration of applicable notice and cure periods under this Sublease,
either Sublandlord or Subtenant may exercise the rights granted to Sublandlord
(as Tenant under the Overlease) under clauses (i) and (ii) of Article 10 of the
Overlease; provided, further, that if Subtenant elects to not exercise any such
rights and Sublandlord does elect to exercise such rights, Subtenant shall be
released from any further obligations arising hereunder and this Sublease shall
terminate and expire). Sublandlord shall promptly provide to Subtenant copies of
all amendments and modifications of the Overlease to the extent same affects the
rights or obligations of Subtenant.

                  D. (i) This Sublease is expressly made subject and subordinate
to all of the terms and conditions of any Leasehold Mortgage (as hereinafter
defined), provided, however, that such subordination is conditioned upon the
holder of any such Leasehold Mortgage delivering to Subtenant a Nondisturbance
Agreement (as hereinafter defined), in form reasonably satisfactory to such
Leasehold Mortgagee, Sublandlord and Subtenant (but in any event subject to
clause (iii) below). Sublandlord shall use its reasonable efforts to obtain from
each holder of a mortgage of Sublandlord's interest in the Overlease (a
"LEASEHOLD MORTGAGE") an agreement to the effect that, if there shall be a
foreclosure of its Leasehold Mortgage, the holder of such Leasehold Mortgage
will not make Subtenant a party defendant to such foreclosure, evict Subtenant,
disturb Subtenant's possession under this Sublease, or terminate or disturb
Subtenant's leasehold estate or rights hereunder, and will recognize Subtenant
as the direct tenant of the holder of such Leasehold Mortgage on the same terms
and conditions as are contained in this Sublease, subject to the provisions
hereinafter set forth, provided no default shall have occurred and be continuing
hereunder (any such agreement, or any agreement of similar import, from the
holder of a Leasehold Mortgage being hereinafter referred to as a
"NONDISTURBANCE AGREEMENT").

         (ii)     Sublandlord shall have no liability to Subtenant for its
failure to obtain any Nondisturbance Agreement referred to in subparagraph (i)
above. Sublandlord's agreement to use reasonable efforts under this subparagraph
D shall not impose any obligation upon Sublandlord (y) to incur any cost or
expense or (z) to institute any legal or other proceeding in connection with
obtaining such Nondisturbance Agreement.

         (iii)    Any Nondisturbance Agreement may be made on the condition that
the holder of the Leasehold Mortgage, or anyone claiming by, through or under
such holder, including a purchaser at a foreclosure sale, shall not be:

                  (a) liable for any act or omission of any prior landlord
(including, without limitation, the then defaulting landlord) except to the
extent such act or omission continues after the effective date of such transfer,
or

                  (b) subject to any defense or offsets which Subtenant may have
against any prior landlord (including, without limitation, the then defaulting
Sublandlord), or


                                       6

                  (c) bound by any payment of Fixed Rent or additional rent
which tenant may have made to any prior landlord (including, without limitation,
the then defaulting Sublandlord) more than thirty (30) days in advance of the
date upon which such payment was due (except to the extent such payment is
recovered by such successor to Sublandlord), or

                  (d) bound by any obligation to make any payment to or on
behalf of Subtenant which was required to be made prior to the time such
successor to Sublandlord succeeded to Sublandlord's interest, or

                  (e) bound by any obligation to perform any work or to make
improvements to the Sublease Premises, or

                  (f) bound by any amendment or modification of this Sublease
made without its consent, or

                  (g) bound to return Subtenant's security deposit, if any,
until such deposit has come into its actual possession and Subtenant would be
entitled to such security deposit pursuant to the terms of this Sublease.

         (iv)     If required by the holder of a Leasehold Mortgage, within ten
(10) business days after notice thereof, Subtenant shall join in any
Nondisturbance Agreement to indicate its concurrence with the provisions thereof
and its agreement in the event of a foreclosure of such Leasehold Mortgage or
the granting of a deed in lieu to attorn to such mortgagee or to any person
acquiring the interest of Sublandlord in the Overlease as Subtenant's landlord
hereunder. Any such Nondisturbance Agreement may also contain other terms and
conditions as may otherwise be required by such holder which do not increase
Subtenant's monetary obligations under this Sublease, or increase Subtenant's
non-monetary obligations under this Sublease in any material respect, or
adversely affect or diminish Subtenant's rights in any material respect.

         6.       Electricity.

                  A. Subtenant shall, at its sole cost and expense, obtain
directly from the public utility company furnishing electric service to the
Building all electric energy used or to be used in the Sublease Premises.
Sublandlord represents that it is currently obtaining electricity directly from
Con Edison. Promptly following the Commencement Date, Sublandlord shall
cooperate with Subtenant to cause the applicable Con Edison accounts currently
existing in respect of the Sublease Premises to be assigned into Subtenant's
name. Sublandlord shall not be liable or responsible to Subtenant for any loss,
damage or expense which Subtenant may sustain or incur if (i) the supply of
electric energy to the Sublease Premises is temporarily interrupted, or (ii) the
quantity or character of electric service is changed or is no longer available
or suitable for Subtenant's requirements, except to the extent that the same was
caused by the negligent or wrongful act of Sublandlord. Subtenant's use of
electricity within the Sublease Premises shall never exceed the capacity of the
then existing


                                       7

wires, feeders or other electrical equipment serving the Sublease Premises. In
the event Subtenant is legally unable to obtain electric service directly from
the utility company servicing the Sublease Premises, Sublandlord shall install
sub-meters, at Subtenant's sole cost and expense, to measure Subtenant's
consumption of electrical energy and use reasonable efforts to cause
Overlandlord to supply electricity to the Sublease Premises. If Sublandlord does
so, Subtenant shall pay to Sublandlord, as additional rent, within fifteen (15)
days after demand, from time to time, but no more frequently than monthly, for
its consumption and demand of electrical energy at the rate which Sublandlord
pays to the utility serving the Building as evidenced by such submeter (plus all
of Sublandlord's actual out of pocket costs in connection with the
administration thereof). For the purpose hereof the rate to be paid by Subtenant
in the event of sub-metering shall include any taxes or other charges in
connection therewith. If any tax shall be imposed upon Sublandlord's receipts
from the sale or resale of electrical energy to Subtenant, the pro rata share
allocable to the electrical energy service received by Subtenant shall be passed
on to, included in the bill of, and paid by Subtenant if and to the extent
permitted by law. Where more than one meter measures the electricity supplied to
Subtenant, the electricity rendered through each meter may be computed and
billed separately in accordance with the provisions hereinabove set forth.
Subtenant expressly acknowledges that, in connection with the installation of
the sub-meters, the electricity being furnished to the Sublease Premises may be
temporarily interrupted. Sublandlord shall use reasonable efforts to minimize
interference with the conduct of Subtenant's business in connection with such
installation, but the foregoing shall not require Sublandlord to utilize premium
or overtime labor in connection therewith. If following the installation of
submeters, Sublandlord is prohibited from selling or reselling electrical energy
to Subtenant, Sublandlord may, upon reasonable prior notice to Subtenant, if
practicable, remove the submeters and Sublandlord shall have no further
obligation to Subtenant in respect of electricity service.

                  B. Without limiting the terms of Subparagraph 4B, except as
otherwise expressly provided in this Article 6, the terms of Article 4 of the
Overlease (as amended by paragraph 2 of the First Amendment) shall be
incorporated by reference in this Sublease as if fully stated herein. As
incorporated herein, there shall be substituted in said Article 4 (i)
Sublandlord for Overlandlord, (ii) Subtenant for Sublandlord and (iii) Sublease
Premises for Premises.

         7.       Occupancy Tax. If any commercial rent or occupancy tax shall
be levied with regard to the Sublease Premises during the Term, Subtenant shall
pay the same either to the taxing authority, or, if appropriate, to Sublandlord,
as additional rent, not less than ten (10) days before the due date of each and
every such tax payment. In the event that any such tax payment shall be made by
Subtenant to Sublandlord, Sublandlord shall remit the amount of such payment to
the taxing authority on Subtenant's behalf.

         8.       Non-Applicability of Certain Provisions of the Overlease.

                  The following provisions of the Overlease shall not be
incorporated in this Sublease by reference: the Lease Summary Sheet, Articles
1(a), 2, 3(a), 3(b), 3(c), 3(d),


                                       8

3(i), the first three (3) lines of Section 5(a) up and until the word "Tenant"
appearing on such line, 18, 19, 23, 24(a), and 24(b).

         9.       Assignment and Subletting.

                  A. Prohibition Without Consent. Subtenant may, without
Sublandlord's consent, but subject to the terms of this Article 9 and to
Overlandlord's consent in accordance with the Overlease, assign, mortgage,
pledge, encumber or otherwise transfer this Sublease, or sublet the Sublease
Premises or any part thereof to be used or occupied by others (whether for desk
space, mailing privileges or otherwise), provided that as of the effective date
of such proposed assignment or subletting Subtenant is not in default of any of
Subtenant's obligations under this Sublease (after notice and expiration of
applicable grace periods). If this Sublease be assigned, or if the Sublease
Premises or any part thereof be underlet or occupied by anybody other than
Subtenant, Sublandlord may, after default by Subtenant, collect rent from the
assignee, undertenant or occupant, and apply the net amount collected to the
Fixed Rent herein reserved, but no assignment, underletting, occupancy or
collection shall be deemed a waiver of the provisions hereof, the acceptance of
the assignee, undertenant or occupant as Subtenant, or a release of Subtenant
from the further performance by Subtenant of covenants on the part of Subtenant
herein contained. In no event shall any permitted subtenant assign or encumber
its sublease or further sublet all or any portion of its sublet space, or
otherwise suffer or permit the sublet space or any part thereof to be used or
occupied by others, without Overlandlord's prior written consent in each
instance. Any assignment, sublease, mortgage, pledge, encumbrance or transfer in
contravention of the provisions of this Article 9 shall be void.

                  B. Notice of Proposed Transfer.

                           1. If Subtenant shall at any time or times during the
Term desire to assign this Sublease or sublet all or part of the Sublease
Premises, Subtenant shall give notice thereof to Sublandlord, which notice shall
be accompanied by (i) a conformed or photostatic copy of the proposed assignment
or sublease, the effective or commencement date of which shall be not less than
forty-five (45) nor more than one hundred and twenty (120) days after the giving
of such notice, (ii) a statement setting forth in reasonable detail the identity
of the proposed assignee or subtenant, the nature of its business and its
proposed use of the Sublease Premises, (iii) an agreement by Subtenant to
indemnify Sublandlord against liability resulting from any claims that may be
made against Sublandlord by the proposed assignee or subtenant or by any brokers
or other persons claiming a commission or similar compensation in connection
with the proposed assignment or sublease, except for any liability arising from
Sublandlord's negligence or willful misconduct, and (iv) in the case of a
sublease, such additional information related to the proposed subtenant as
Overlandlord shall reasonably request, if any.

                           2. As a condition to any assignment or sublease,
Sublandlord must obtain Overlandlord's consent in accordance with the provisions
of Article 18 of the Overlease. Sublandlord agrees to deliver to Overlandlord
copies of all information provided by Subtenant


                                       9

in connection with any proposed assignment or sublease within 2 Business Days
after receipt of same from Subtenant. Sublandlord further agrees to provide
Subtenant with any requests for additional information or other communications
from Overlandlord immediately upon receipt of same.

                  C. Conditions.

         Each subletting pursuant to this subsection C of this Article 9 shall
be subject to all of the covenants, agreements, terms, provisions and conditions
contained in this Sublease. Notwithstanding any assignment or subletting to any
subtenant and/or acceptance of Fixed Rent or additional rent by Sublandlord from
any subtenant, Subtenant shall and will remain fully liable for the payment of
the Fixed Rent and additional rent due and to become due hereunder and for the
performance of all the covenants, agreements, terms, provisions and conditions
contained in this Sublease on the part of Subtenant to be performed and all acts
and omissions of any licensee or subtenant or anyone claiming under or through
any subtenant which shall be in violation of any of the obligations of this
Sublease shall be deemed to be a violation by Subtenant. Subtenant further
agrees that notwithstanding any such subletting, no other and further subletting
of the Sublease Premises by Subtenant or any person claiming through or under
Subtenant shall or will be made except upon compliance with and subject to the
provisions of this Article 9.

                  D. Sublease Provisions. With respect to each and every
sublease or subletting authorized by Sublandlord under the provisions of this
Sublease, it is further agreed that:

                           (i) No subletting shall be for a term ending later
than one (1) day prior to the Expiration Date of this Sublease;

                           (ii) No sublease shall be effective, and no subtenant
shall take possession of the Sublease Premises or any part thereof, until an
executed counterpart of such sublease has been delivered to Sublandlord;

                           (iii) Each sublease shall provide that it is subject
and subordinate to this Sublease and to the matters to which this Sublease is or
shall be subordinate, and that in the event of termination, re-entry or
dispossession by Sublandlord under this Sublease Sublandlord may, at its option,
take over all of the right, title and interest of Subtenant, as sublessor, under
such sublease, and such subtenant shall, at Sublandlord's option, attorn to
Sublandlord pursuant to the then executory provisions of such sublease, except
that Sublandlord shall not (a) be liable for any previous act or omission of
Subtenant under such sublease, (b) be subject to any counterclaim, offset or
defense, not expressly provided in such sublease, which theretofore accrued to
such subtenant against Subtenant, or (c) be bound by any previous modification
of such sublease or by any previous prepayment of more than one (1) month's
Fixed Rent, except to the extent received by Sublandlord. The provisions of this
Article 9 shall be self-operative and no further instrument shall be required to
give effect to this provision.


                                       10

                  E. Other Transfers. (i) If Subtenant is a corporation other
than a corporation whose stock is listed and traded on a nationally recognized
stock exchange (hereinafter referred to as a "public corporation"), the
provisions of subsection A of this Article 9 shall apply to a transfer (by one
or more transfers) of a majority of the stock of Subtenant as if such transfer
of a majority of the stock of Subtenant were an assignment of this Sublease; but
said provisions shall not apply to transactions with a corporation into or with
which Subtenant is merged or consolidated or to which substantially all of
Subtenant's assets are transferred, provided that in any of such events (a) the
successor to Subtenant has a net worth computed in accordance with generally
accepted accounting principles at least equal to the greater of (1) the net
worth of Subtenant immediately prior to such merger, consolidation or transfer,
or (2) the net worth of Subtenant herein named on the date of this Sublease and
(b) proof satisfactory to Sublandlord of such net worth shall have been
delivered to Sublandlord at least ten (10) days prior to the effective date of
any such transaction.

                           (ii) If Subtenant is a partnership, the provisions of
subsection A of this Article 9 shall apply to a transfer (by one or more
transfers) of a majority interest in the partnership, as if such transfer were
an assignment of this Sublease.

                           (iii) If Subtenant is a subdivision, authority, body,
agency, instrumentality or other entity created and/or controlled pursuant to
the laws of the State of New York or any city, town or village of such state or
of federal government ("Governmental Entity"), the provisions of subsection A of
this Article 9 shall apply to a transfer (or one or more transfers) of any of
Subtenant's rights to use and occupy the Sublease Premises, to any other
Governmental Entity, as if such transfer of the right of use and occupancy were
an assignment of this Sublease; but said provisions shall not apply to a
transfer of any of Subtenant's rights in and to the Sublease Premises to any
Governmental Entity which shall replace or succeed to substantially similar
public functions, responsibilities and areas of authority as Subtenant, provided
that in any of such events the successor Governmental Entity shall utilize the
Sublease Premises in a manner substantially similar to Subtenant.

                  F. Assumption by Assignee. Any assignment or transfer, shall
be made only if, and shall not be effective until, the assignee shall execute,
acknowledge and deliver to Sublandlord an agreement in form and substance
reasonably satisfactory to Sublandlord whereby the assignee shall assume the
obligations of this Sublease on the part of Subtenant to be performed or
observed and whereby the assignee shall agree that the provisions in subsection
A of this Article 9 shall, notwithstanding such assignment or transfer, continue
to be binding upon it in respect of all future assignments and transfers. The
original named Subtenant covenants that, notwithstanding any assignment or
transfer, whether or not in violation of the provisions of this Sublease, and
notwithstanding the acceptance of Fixed Rent and/or additional rent by
Sublandlord from an assignee, transferee or any other party, the original named
Subtenant shall remain fully liable for the payment of the Fixed Rent and
additional rent and for the other obligations of this Sublease on the part of
Subtenant to be performed or observed.


                                       11

                  G. Liability of Subtenant. The joint and several liability of
Subtenant and any immediate or remote successor in interest of Subtenant and the
due performance of the obligations of this Sublease on Subtenant's part to be
performed or observed shall not be discharged, released or impaired in any
respect by any agreement or stipulation made by Sublandlord extending the time,
or modifying any of the obligations, of this Sublease, or by any waiver or
failure of Sublandlord to enforce any of the obligations of this Sublease.

                  H. Re-entry by Sublandlord. If Sublandlord shall recover or
come into possession of the Sublease Premises before the date herein fixed for
the termination of this Sublease, Sublandlord shall have the right, at its
option, to take over any and all subleases or sublettings of the Sublease
Premises or any part thereof made by Subtenant and to succeed to all the rights
of said subleases and sublettings or such of them as it may elect to take over.
Subtenant hereby expressly assigns and transfers to Sublandlord such of the
subleases and sublettings as Sublandlord may elect to take over at the time of
such recovery of possession, such assignment and transfer not to be effective
until the termination of this Sublease or re-entry by Sublandlord hereunder or
if Sublandlord shall otherwise succeed to Subtenant's estate in the Sublease
Premises, at which time Subtenant shall upon request of Sublandlord, execute,
acknowledge and deliver to Sublandlord such further instruments of assignment
and transfer as may be necessary to vest in Sublandlord the then existing
subleases and sublettings. Every subletting hereunder is subject to the
condition and by its acceptance of and entry into a sublease, each subtenant
thereunder shall be deemed conclusively to have thereby agreed from and after
the termination of this Sublease or re-entry by Sublandlord hereunder of or if
Sublandlord shall otherwise succeed to Subtenant's estate in the Sublease
Premises, that such subtenant shall waive any right to surrender possession or
to terminate the sublease and, at Sublandlord's election, such subtenant shall
be bound to Sublandlord for the balance of the term of such sublease and shall
attorn to and recognize Sublandlord, as its Sublandlord, under all of the then
executory terms of such sublease, except that Sublandlord shall not (i) be
liable for any previous act, omission or negligence of Subtenant under such
sublease, (ii) be subject to any counterclaim, defense or offset not expressly
provided for in such sublease, which theretofore accrued to such subtenant
against Subtenant, (iii) be bound by any previous modification or amendment of
such sublease or by any previous prepayment of more than one (1) month's Fixed
Rent and additional rent which shall be payable as provided in the sublease,
(iv) be obligated to repair the subleased space or the Building or any part
thereof, in the event of total or substantial total damage beyond such repair as
can reasonably be accomplished from the net proceeds of insurance actually made
available to Sublandlord, (v) be obligated to repair the subleased space or the
Building or any part thereof, in the event of partial condemnation beyond such
repair as can reasonably be accomplished from the net proceeds of any award
actually made available to Sublandlord as consequential damages allocable to the
part of the subleased space or the Building not taken or (vi) be obligated to
perform any work in the subleased space of the Building or to prepare them for
occupancy beyond Sublandlord's obligations under this Sublease, and the
subtenant shall execute and deliver to Sublandlord any instruments Sublandlord
may reasonably request to evidence and confirm such attornment. Each subtenant
or licensee of Subtenant shall be deemed automatically upon and as a condition
of occupying or using the Sublease Premises or any part thereof, to have given a
waiver of the type described in and to the extent and upon the conditions set
forth in this Article 9.


                                       12

         10.      Insurance.

                  A. Subtenant shall, with respect to the Sublease Premises,
obtain at its own expense and keep in full force and effect during the Term,
each and every policy of insurance required to be carried by the lessee pursuant
to Article 9 of the Overlease (including, without limitation, any increase in
coverage which may be required by Overlandlord pursuant to the terms thereof)
under which Subtenant is named as the insured, and Overlandlord, Sublandlord,
Sublandlord's asset manager (Savanna Asset Management LLC or any successor
thereto), the present and any future mortgagee of the Real Property or the
Building and/or such other designees specified by Sublandlord from time to time,
are named as additional insureds.

                  B. Notwithstanding anything to the contrary contained in
Article 9 of the Overlease, and notwithstanding the limits of insurance
specified in this Paragraph 10, Subtenant agrees to defend, indemnify and hold
harmless Sublandlord, and the agents, partners, shareholders, directors,
officers and employees of Sublandlord, from and against all damage, loss,
liability, cost and expense (including, without limitation, engineers',
architects' and attorneys' fees and disbursements) resulting from any of the
risks referred to in this Paragraph 10 and Article 9 of Overlease. Such
indemnification shall operate whether or not Subtenant has placed and maintained
the insurance specified in this Paragraph 10, and whether or not proceeds from
such insurance (such insurance having been placed and maintained) actually are
collectible from one or more of the aforesaid insurance companies; provided,
however, that Subtenant shall be relieved of its obligation of indemnity herein
pro tanto of the amount actually recovered by Sublandlord from one or more of
said insurance companies by reason of injury or damage to or loss sustained on
the Sublease Premises.

                  C. Subtenant hereby agrees to indemnify, hold harmless and
defend Sublandlord, its officers, directors, employees, agents and contractors
(the "Sublandlord Parties") from and against any and all claims, damages,
liabilities, costs and expenses (including, but not limited to, attorneys' fees
and disbursements) arising as a result of (i) any breach by Subtenant of any of
the representations, warranties, covenants and agreements of Subtenant under
this Sublease, or (ii) the conduct of business in or management of the Sublease
Premises during the Term or while Subtenant is in possession of or otherwise
occupies all or any pat of the Sublease Premises, or (iii) any work or thing
whatsoever done or any condition created in or about the Sublease Premises
during the Term or while Subtenant is in possession of or otherwise occupies all
or any part of the Sublease Premises, or (iv) any negligent or willful act or
omission of Subtenant or of any licensee or invitee or other occupant of, or
person present at, the Sublease Premises or of any employee, agent or contractor
of any of the foregoing during the Term or while Subtenant is in possession of
or otherwise occupies all or any part of the Sublease Premises. Notwithstanding
the foregoing, Subtenant shall not indemnify the Sublandlord Parties against any
negligence or willful misconduct of any of the Sublandlord Parties.

                  D. Each of Subtenant and Sublandlord shall procure an
appropriate clause in or endorsement to any property insurance covering the
Premises demised under the


                                       13

Overlease, the Sublease Premises and any personal property, fixtures, and
equipment located therein, wherein the insurance companies shall waive
subrogation or consent to a waiver of right of recovery, and Sublandlord and
Subtenant agree not to make any claim against, or to seek to recover from, the
other, for any loss or damage to its property or the property of others
resulting from fire and other hazards to the extent covered by such property
insurance; provided, however, that the release, discharge, exoneration and
covenant not to sue contained herein shall be limited by and coextensive with
the terms and provisions of the waiver or subrogation or waiver of right of
recovery.

         11. Brokerage. Subtenant represents and warrants to Sublandlord, and
Sublandlord represents and warrants to Subtenant, that no broker, other than
Spaceworks Real Estate Services, Inc. and Outer Boro Brokerage, Inc.
(collectively, the "BROKER"), was instrumental in consummating this Sublease,
and that no conversations or prior negotiations were had with any broker other
than the Broker concerning the subletting of the Sublease Premises. Subtenant
shall indemnify and hold Sublandlord harmless from and against, and Sublandlord
shall indemnify and hold Subtenant harmless from and against, any claims for
brokerage commissions or similar fees claimed by any person or entity other than
the Broker and any and all other claims, damages, liabilities, costs and
expenses (including, without limitation, attorneys' fees and disbursements)
arising out of or in connection with the breach of the foregoing representations
and warranties, respectively. A commission in respect of this Sublease shall be
paid to Broker by Sublandlord pursuant to separate agreement.

         12. Assignment of the Overlease. The term "Sublandlord" as used in this
Sublease means only the tenant under the Overlease, at the time in question, so
that if Sublandlord's interest in the Overlease is assigned, Sublandlord shall
be thereupon released and discharged from all covenants, conditions and
agreements of Sublandlord hereunder accruing with respect to the Overlease from
and after the date of such assignment, but such covenants, conditions and
agreements shall be binding on the assignee until thereafter assigned.

         13. Notices and Cure Periods; Default and Remedies.

                  A. All notices hereunder to Sublandlord or Subtenant shall be
given in writing and delivered by hand, national overnight courier or mailed by
certified or registered mail, return receipt requested, to the addresses set
forth below:

         If to Sublandlord:

         325 Spring Street LLC
         c/o Savanna Partners
         80 Fifth Avenue
         New York, New York
         Attn: Christopher Schlank


                                       14

with a copy to:

         Solomon and Weinberg LLP
         685 Third Avenue
         New York, New York 10017
         Attn: Jay Stark, Esq.

         If to Subtenant:

         ImClone Systems Incorporated
         180 Varick Street
         New York, New York
         Attn: John B. Landes, General Counsel

with a copy to:

         Morrison Cohen Singer & Weinstein, LLP
         750 Lexington Avenue
         New York, New York 10022
         Attn: Laurie F. Golub, Esq.

                  B. By notice given in the aforesaid manner, either party
hereto may notify the other as to any change as to where and to whom such
party's notices are thereafter to be addressed.

                  C. The effective date of any notice shall be the date such
notice is delivered (if by hand or by national overnight courier) or three (3)
days after the date of mailing thereof.

                  D. In connection with the incorporation by reference of notice
and other time limit provisions of the Overlease into this Sublease (and except
with respect to actions to be taken by Subtenant for which shorter time limits
are specifically set forth in this Sublease, which time limits shall control for
the purposes of this Sublease), the time limits provided in the Overlease for
the giving or making of any notice by the tenant thereunder to Overlandlord, the
holder of any mortgage, the lessor under any ground or underlying lease or any
other party, or for the performance of any act, condition or covenant or the
curing of any default by the tenant thereunder, or for the exercise of any
right, remedy or option by the tenant thereunder, are changed for the purposes
of this Sublease, by shortening the same in each instance: (i) to fifty (50)
calendar days with respect to all such periods of sixty (60) or more calendar or
business days, (ii) to twenty (20) calendar days with respect to all such
periods of thirty (30) or more calendar or business days but less than sixty
(60) calendar or business days, (iii) to fifteen (15) calendar days with respect
to all such periods of twenty (20) or more calendar or business days but less
than thirty (30) calendar or business days, (iv) to seven (7) calendar days with
respect to all such periods of ten (10) or more calendar or business days but
less than twenty (20) calendar or business days, and (v) to three (3) business


                                       15

days with respect to all such periods of five (5) or more calendar or business
days but less than ten (10) calendar or business days; but in any and all events
to a time limit enabling Sublandlord to give any notice, perform any act,
condition or covenant, cure any default, and/or exercise any option within the
time limit relating thereto as contained in the Overlease. Subtenant shall,
immediately upon receipt thereof, notify Sublandlord of any notice served by
Overlandlord upon Subtenant under any of the provisions of the Overlease or with
reference to the Sublease Premises. Sublandlord shall, immediately upon receipt
thereof, notify Subtenant of any notice of default served by Overlandlord upon
Sublandlord under any of the provisions of the Overlease or with reference to
the Sublease Premises. Subtenant shall immediately furnish notice to Sublandlord
of any action taken by Subtenant to cure any default under, or comply with any
request or demand made by Overlandlord and/or Sublandlord in connection with the
Overlease (pertaining to the Sublease Premises) or this Sublease.

                  E. Article 14 of the Overlease as incorporated herein by
reference is hereby modified (i) by the words "five (5) days" appearing in
subsection (a) thereof being deleted and the words "three (3) business days"
being inserted in lieu thereof; (ii) by the words "twenty (20) days" appearing
in subsection (a) thereof being deleted and the words "fifteen (15) days" being
inserted in lieu thereof; (iii) by the words "thirty (30) days" appearing in
subsection (j) thereof being deleted and the words "twenty (20) days" being
inserted in lieu thereof; and (iv) by the words "ninety (90) days" appearing in
subsection (j) thereof being deleted and the words "eighty (80) days" being
inserted in lieu thereof.

                  F. (i) If this Sublease shall be terminated under the
provisions of Article 15 of the Overlease as incorporated herein:

                           (a) Subtenant shall quit and peacefully surrender the
Sublease Premises to Sublandlord, and Sublandlord and its agents may
immediately, or at any time after such termination or after the date upon which
this Sublease and the Term shall expire and come to an end, re-enter the
Sublease Premises or any part thereof, without notice, either by summary
proceedings, or by any other applicable action or proceeding, or by force or
otherwise (without being liable to indictment, prosecution or damages thereof
or), and may repossess the Sublease Premises and dispossess Subtenant and any
other persons from the Sublease Premises and remove any and all of their
property and effects from the Sublease Premises; and

                           (b) Sublandlord, at Sublandlord's option, may relet
the whole or any part or parts of the Sublease Premises from time to time,
either in the name of Sublandlord or otherwise, to such subtenant or subtenants,
for such term or terms ending before, on or after the Expiration Date, at such
rental or rentals and upon such other conditions, which may include concessions
and free rent periods, as Sublandlord, in its sole discretion, may determine;
provided, however, that Sublandlord shall have no obligation to relet the
Sublease Premises or any part thereof and shall in no event be liable for
refusal or failure to relet the Sublease Premises or any part thereof, or, in
the event of any such reletting, for refusal or failure to collect any rent due
upon any such reletting, and no such refusal or failure shall operate to relieve
Subtenant of any liability under this Sublease or otherwise affect any


                                       16

such liability, and Sublandlord, at Sublandlord's option, may make such repairs,
replacements, alterations, additions, improvements, decorations and other
physical changes in and to the Sublease Premises as Sublandlord, in its sole
discretion, considers advisable or necessary in connection with any such
reletting or proposed reletting, without relieving Subtenant of any liability
under this Sublease or otherwise affecting any such liability.

                           (ii) Subtenant hereby waives the service of any
notice of intention to re-enter or to institute legal proceedings to that end
which may otherwise be required to be given under any present or future law.
Subtenant, on its own behalf and on behalf of all persons claiming through or
under Subtenant, including all creditors, does further hereby waive any and all
rights which Subtenant and all such persons might otherwise have under any
present or future law to redeem the Sublease Premises, or to re-enter or
repossess the Sublease Premises, or to restore the operation of this Sublease,
after (a) Subtenant shall have been dispossessed by a judgment or by warrant of
any court or judge, or (b) any re-entry by Sublandlord, or (c) any expiration or
termination of this Sublease and the Term, whether such dispossess, re-entry,
expiration or termination shall be by operation of law or pursuant to the
provisions of this Sublease. The words "reenter," re-entry" and "re-entered" as
used in this Sublease shall not be deemed to be restricted to their technical
legal meanings. In the event of a breach or threatened breach by Subtenant, or
any persons claiming through or under Subtenant, of any term, covenant or
condition of this Sublease, Sublandlord shall have the right to enjoin such
breach and the right to invoke any other remedy allowed by law or in equity as
if re-entry, summary proceedings and other special remedies were not provided in
this Sublease for such breach. The rights to invoke the remedies hereinbefore
set forth are cumulative and shall not preclude Sublandlord from invoking any
other remedy allowed at law or in equity.

                           (iii) If this Sublease and the Term shall expire and
come to an end as provided in Article 15 of the Overlease as incorporated herein
or in this Subparagraph 13F, or by or under any summary proceeding or any other
action or proceeding, or if Sublandlord shall re-enter the Sublease Premises as
provided in said Article 15 as incorporated herein or this Subparagraph 13F, or
by or under any summary proceeding or any other action or proceeding, then, in
any of said events:

                                    (a) Subtenant shall pay to Sublandlord all
rent (including additional rent) and other items payable under this Sublease by
Subtenant to Sublandlord to the date upon which this Sublease and the Term shall
have expired and come to an end or to the date of re-entry upon the Sublease
Premises by Sublandlord, as the case may be;

                                    (b) Subtenant also shall be liable for and
shall pay to Sublandlord, as damages, any deficiency (referred to as
"DEFICIENCY") between the rent (including additional rent) for the period which
otherwise would have constituted the unexpired portion of the Term and the net
amount, if any, of rents collected under any reletting effected pursuant to the
provisions of clause (a) of sub-subparagraph 13F(i) hereof for any part of such
period (first deducting from the rents collected under any such reletting all of


                                       17

Sublandlord's expenses in connection with the termination of this Sublease,
Sublandlord's reentry upon the Sublease Premises and with such reletting
including, but not limited to, all repossession costs, brokerage commissions,
legal expenses, attorneys' fees and disbursements, alteration costs and other
expenses of preparing the Sublease Premises for such reletting); any such
Deficiency shall be paid in monthly installments by Subtenant on the days and in
the manner specified in this Sublease for payment of monthly installments of
Fixed Rent, Sublandlord shall be entitled to recover from Subtenant each monthly
Deficiency as the same shall arise, and no suit to collect the amount of the
Deficiency for any month shall prejudice Sublandlord's right to collect the
Deficiency for any subsequent month by a similar proceeding; and

                                    (c) whether or not Sublandlord shall have
collected any monthly Deficiency as aforesaid, Sublandlord shall be entitled to
recover from Subtenant, and Subtenant shall pay to Sublandlord, on demand, in
lieu of any further Deficiency as and for liquidated and agreed final damages, a
sum equal to the amount by which the rent (including additional rent) for the
period which otherwise would have constituted the unexpired portion of the Term
exceeds the then fair and reasonable rental value of the Sublease Premises for
the same period, both discounted to present worth at the 4% per annum, less the
aggregate amount of Deficiencies theretofore collected by Sublandlord pursuant
to the provisions of clause (b) of sub-subparagraph 13 F(iii) hereof for the
same period; if, before presentation of proof of such liquidated damages to any
court, commission or tribunal, the Sublease Premises, or any part thereof, shall
have been relet by Sublandlord for the period which otherwise would have
constituted the unexpired portion of the Term, or any part thereof, the amount
of rent reserved upon such reletting shall be deemed, prima facie, to be the
fair and reasonable rental value for the part or the whole of the Sublease
Premises so relet during the term of the reletting.

                           (iv) If the Sublease Premises, or any part thereof,
shall be relet together with other space in the Building, the rents collected or
reserved under any such reletting and the expenses of any such reletting shall
be equitably apportioned for the purposes of sub-subparagraph 13F(iii) hereof.
Subtenant shall in no event be entitled to any rents collected or payable under
any reletting, whether or not such rents shall exceed the fixed annual rent
reserved in this Sublease.

         14. Binding Effect. The covenants, conditions and agreements contained
in this Sublease shall bind and inure to the benefit of the parties hereto and
their respective legal representatives, successors and assigns (to the extent
permitted hereunder).

         15. Condition of the Sublease Premises.

                  A. It is understood and agreed that all understandings and
agreements heretofore had between the parties are merged in this Sublease, which
alone fully and completely expresses their agreements, and that the same are
entered into after full investigation, neither party relying upon any statement
or representation made by the other and not embodied in this Sublease. Subtenant
agrees to accept possession of the Demised Premises in "as is" and "where is"
condition on the date hereof and Sublandlord is not required to


                                       18

perform work of any kind, nature or description to prepare the Sublease Premises
for Subtenant's occupancy.

                  B. Subtenant acknowledges and agrees that any and all
alterations, installations, renovations or other items of work necessary to
prepare the Sublease Premises for Subtenant's initial occupancy ("Subtenant's
Work") shall be performed by Subtenant (subject to the applicable provisions of
the Overlease), at Subtenant's sole cost and expense.

         16. At End of Term.

         Upon the expiration or sooner termination of the Term, Subtenant shall
vacate and surrender the Sublease Premises in broom clean condition, in good
order and condition and otherwise in accordance with Article 8 of the Overlease
(or any other condition expressly consented to in writing by Overlandlord if
different than the express provisions of Article 8 of the Overlease).

         17. Intentionally Reserved.

         18. Miscellaneous.

                  A. This Sublease is made in the State of New York and shall be
governed by and construed under the laws thereof. This Sublease supersedes any
and all other or prior understandings, agreements, covenants, promises,
representations or warranties of or between the parties (which are fully merged
herein). The headings in this Sublease are for purposes of reference only and
shall not limit or otherwise affect the meaning hereof. Whenever necessary or
appropriate, the neuter gender as used herein shall be deemed to include the
masculine and feminine; the masculine to include the feminine and neuter; the
feminine to include the masculine and neuter; the singular to include the
plural; and the plural to include the singular. This Sublease shall not be
binding upon Sublandlord for any purpose whatsoever unless and until Sublandlord
has delivered to Subtenant a fully executed duplicate original hereof. The
captions appearing in this Sublease have been inserted for convenience only and
shall not control or affect or be deemed part of this Sublease or control or
affect the meaning or construction of any of the terms, conditions or provisions
hereof.

                  B. Tenant Access. Subject to the terms of the Overlease and
the terms of this Sublease, Subtenant shall have access to the Sublease Premises
twenty-four (24) hours per day, seven (7) days per week.

                  C. HVAC Placement. Subject to the express prior written
consent of Overlandlord, Subtenant shall have the non-exclusive right to
install, inspect, adjust and maintain HVAC equipment (the "EQUIPMENT") (or such
other type of Equipment as may be reasonably approved by Overlandlord) on the
Building rooftop at Subtenant's sole risk, cost and expense (said right is
hereinafter referred to as "SUBTENANT'S HVAC Right") provided said Equipment
does not involve any penetration of the roof surface and such installation is
otherwise, in all respects, satisfactory to, Overlandlord and its roofing
contractor. The


                                       19

dimensions and performance characteristics of said Equipment shall be subject
to Overlandlord's approval, in Overlandlord's sole and absolute discretion.
Sublandlord hereby assigns and conveys to Subtenant, for so long as this
Sublease is in full force and effect, all of Sublandlord's rights under the
Overlease in respect of the Building rooftop (including without limitation, the
right to place signage thereon), if any.

                  (a) Roof Access. Sublandlord and Subtenant agree that
Subtenant's HVAC Right will necessitate that Subtenant have access to the
rooftop of the Building. To the extent that Subtenant's HVAC Right expands the
area of the Building to which Subtenant has access (the "new access areas"),
then Sublandlord and Subtenant agree that any and all provisions of the Sublease
that apply to the Sublease Premises, shall also apply to new access areas,
except as modified herein and except to the extent that said Sublease provisions
place any additional responsibilities on the Sublandlord with respect to the new
access areas. The precise location of the Equipment shall be subject to the
approval of Overlandlord in accordance with Articles 6 and 7 of the Overlease.

                  (b) Subtenant's Obligations.

                           (i) Increase in Sublandlord's Insurance Cost. If the
rate of any insurance carried by Sublandlord is increased as a result of the
exercise of Subtenant's HVAC Right, then Subtenant will pay to Sublandlord, as
additional rent, not later than thirty (30) days before the date Sublandlord is
obligated to pay a premium on the insurance or within ten (10) days after
Sublandlord delivers to Subtenant a certified statement from Sublandlord's
insurance carrier stating that the rate increase was caused by Subtenant's HVAC
Right, whichever date is later, a sum equal to the difference between the
original premium and the increased premium resulting solely from the
installation of the Equipment.

                           (ii) Rooftop Access. Sublandlord has not made any
representations or promises pertaining to physical condition of the Building's
rooftop or its suitability for the installation and maintenance of the
Equipment. Subtenant, for the purpose of this Sublease and its right to rooftop
access hereunder, accepts the rooftop in its "as is" condition.

                           (iii) Insurance. Subtenant will, at all times during
the term of this Sublease, and at its cost and expense, ensure that the
insurance policies to be maintained by Subtenant under Section 10 hereof are
properly endorsed to reflect the Equipment and Subtenant's HVAC Right. Subtenant
agrees to pay the premiums therefor and to deliver copies of said policies
and/or endorsements thereto to Sublandlord on the first day of the term of this
Sublease, and the failure of Subtenant to either obtain said insurance or
deliver copies of said policies or certificates thereof to Sublandlord shall be
a default under this Sublease.

                           (iv) Indemnity. Subtenant shall and hereby does
indemnify and hold harmless the Sublandlord against and from any and all claims
arising from the Subtenant's use of the new access areas and Subtenant's
installation, inspection, adjustment and maintenance of the Equipment. Subtenant
assumes all risk of damage to property or injury to


                                       20

persons, in, upon or about the new access areas as a result of Subtenant's
installation, inspection, adjustment and maintenance of the Equipment, except to
the extent caused by the negligence or willful misconduct of Sublandlord, its
agents, employees or contractors.

                           (v) Default. Subtenant's HVAC Right shall terminate
in the event this Sublease terminates.

                           D. Deliveries. Subject to the consent of
Overlandlord, Subtenant shall have the right to use Overlandlord's ramp to
access the third (3rd) floor of the Sublease Premises throughout the Term to
make regularly scheduled deliveries to the Sublease Premises.

                           E. Parking. Sublandlord hereby assigns to Subtenant,
to the extent assignable, and Subtenant hereby assumes from Sublandlord,
Sublandlord's rights and obligations arising under and pursuant to Article 23 of
the Overlease including, without limitation, the indemnity set forth in the
penultimate sentence of Article 23 of the Overlease (pursuant to which
Sublandlord shall also be indemnified against and held harmless by Subtenant).
Sublandlord shall have no liability whatsoever for Overlandlord's failure to
provide the Parking Spaces (as defined in the Overlease), except if due to the
negligence or willful misconduct of Sublandlord.

         19. Valid Authority. Subtenant and Sublandlord each hereby represents
and warrants to the other that:

                           (i) Sublandlord and Subtenant, respectively, is duly
organized, validly existing and in good standing under the laws of the State of
Delaware, and has the full right and authority to enter into this Sublease; and

                           (ii) The execution, delivery and performance of this
Sublease by Sublandlord and Subtenant, respectively: (a) has been duly
authorized, (b) does not conflict with any provisions of any instrument to which
Sublandlord and Subtenant, respectively, is a party or by which Sublandlord or
Subtenant, respectively, is bound, and (c) constitutes a valid, legal and
binding obligation of Sublandlord and Subtenant, respectively.

         20. Failure to Give Possession. If Sublandlord is unable to give
possession of the Sublease Premises to Subtenant on the Commencement Date,
because of any reason, Sublandlord shall not be subject to any liability for
failure to give possession on said date and the validity of this Sublease shall
not be impaired under such circumstances, nor shall the same be construed to
extend the term of this Sublease, but the Fixed Rent shall be abated (provided
that Subtenant is not responsible for the inability to obtain possession) until
Sublandlord shall have delivered possession of the Sublease Premises to
Subtenant. The provisions of this Paragraph are intended to constitute "an
express provision to the contrary" within the meaning of Section 223 a of the
New York Real Property Law.


                                       21

         21. Consent of Overlandlord under the Overlease. This Sublease shall
have no effect (and the Commencement Date shall not be deemed to have occurred)
until Overlandlord shall have given its written consent hereto in accordance
with the terms of the Overlease. If Overlandlord does not give its consent to
this Sublease for any reason whatsoever other than Subtenant's failure to
provide information requested by Overlandlord, within ten (10) days after the
date hereof, then either party may elect to cancel this Sublease by giving
notice to the other party after the expiration of said 10-day period, but prior
to the giving of said consent by Overlandlord to this Sublease. Subtenant
acknowledges that Subtenant will be required to execute and deliver such consent
as a condition precedent to the execution thereof by Overlandlord. Subtenant
agrees that Subtenant shall promptly execute and deliver to Sublandlord
Overlandlord's consent to this Sublease, provided (a) such consent is in the
form more particularly set forth on SCHEDULE 2 attached hereto and made a part
hereof (the "SUBLEASE CONSENT"), and (b) contemporaneously therewith or prior
thereto, Overlandlord shall execute and deliver to Sublandlord and Subtenant an
estoppel certificate in the form more particularly set forth on Schedule 3
attached hereto and made a part hereof (the "LANDLORD ESTOPPEL"). Subtenant's
execution of such consent shall be deemed to be Subtenant's acceptance of the
resolution of such matters and Subtenant shall not, after executing such
consent, have the right to terminate this Sublease based on any allegations that
such matters have not been consented to by Overlandlord. If either party shall
have given notice of cancellation to the other party (in accordance with the
provisions of this Paragraph 21), then: (i) neither Sublandlord nor Subtenant
shall be obligated to take any further action to obtain such consent, (ii)
Sublandlord shall refund to Subtenant the installment of Fixed Rent paid by
Subtenant at the execution of this Sublease, and (iii) this Sublease shall
thereupon be deemed null and void and of no further force and effect, and
neither of the parties hereto shall have any rights or claims against the other.
It is expressly agreed that Overlandlord's delivery of the Sublease Consent and
Landlord Estoppel shall be a condition to Subtenant's obligations hereunder.

         22. Renewal Options. The terms and provisions of Articles 26 and 27 of
the Overlease are hereby incorporated herein by reference, mutatis mutandis,
except that (a) the Fixed Rent payable by Subtenant for each of the First
Extension Term (as defined in the Overlease) and the Second Extension Term (as
defined in the Overlease), respectively, shall be equal to ninety-five (95%)
percent of the Fair Market Rent (as defined in the Overlease) and (b)
Subtenant's Renewal Option shall be effective only if Sublandlord has
effectively exercised Sublandlord's Renewal Option pursuant to Article 26 of the
Overlease, it being understood and agreed that Sublandlord shall (y) promptly
and timely exercise Sublandlord's Renewal Option pursuant to Article 26 of the
Overlease promptly after the exercise by Subtenant of its option under this
Paragraph 22, and (z) shall have no obligation to exercise Sublandlord's Renewal
Option, nor shall Subtenant have the renewal option contemplated by this
Paragraph 22 if either (1) at the time of the giving of the First Extension
Notice (as defined in the Overlease) or the Second Extension Notice (as defined
in the Overlease), as the case may be, or at the time of the First Extension
Term or the Second Extension Term, as the case may be, there exists a default by
Subtenant under this Sublease beyond the expiration of the applicable notice and
cure periods or (2) the First Extension Notice is delivered by Subtenant to
Sublandlord on


                                       22

or after April 16, 2022, or the Second Extension Notice is delivered by
Subtenant to Sublandlord on or after April 16, 2027, as the case may be."

         23. Right of First Offer. In the event Sublandlord intends to sublease
the portion of the premises demised to Sublandlord under the Overlease which
does not constitute the Sublease Premises (the "NON-SUBLEASE PREMISES"), and
provided Sublandlord intends to sublease the Non-Sublease Premises for
non-retail use only, Sublandlord shall notify Subtenant in writing (a "ROFO
NOTICE") of such intention. If Sublandlord and Subtenant have not entered into a
term sheet for the subleasing by Subtenant of the Non-Sublease Premises within
fifteen (15) days of the receipt by Subtenant of such ROFO Notice, Time Being of
the Essence, Subtenant's rights with respect to the Non-Sublease Premises shall
be null and void, and Sublandlord shall have the right to enter into a
transaction in respect of the Non-Sublease Premises with any party and on any
terms as Sublandlord shall elect in its sole discretion. Upon delivery by
Sublandlord to Subtenant of a ROFO Notice, Sublandlord and Subtenant shall
endeavor to negotiate the aforementioned term sheet within such fifteen (15) day
period in good faith.

         24. Cooperation. Sublandlord, as lessee of the Non-Sublease Premises
and in respect thereof, and Subtenant, in respect of the Sublease Premises,
shall each use commercially reasonable efforts to minimize interference with the
other party's use of its respective demised premises. Without limiting the
foregoing, (a) if Subtenant shall, in connection with any alterations, repairs,
renovations or other work to be performed to the Sublease Premises, cause to be
installed any scaffolding or other structure to be located on the sidewalk in
front of or adjacent to the Non-Sublease Premises, such scaffolding or other
structure shall be not less than fourteen (14) feet in height (unless otherwise
required by law or to preserve the safety of individuals or property), (b)
notwithstanding anything to the contrary contained in Article 18(C) of this
Sublease, Sublandlord shall be permitted to keep in place the three (3)
condenser units (two (2) on the roof of the Building and one (1) on the roof of
the elevator control room) heretofore installed by Sublandlord on the Building
and install a kitchen exhaust blower on the roof of the elevator control room
(collectively, the "SUBLANDLORD EQUIPMENT"), and to access the Sublandlord
Equipment during the Term (to maintain, repair and replace same), provided that,
(i) Sublandlord shall exercise due care in maintaining, repairing and replacing
same and shall be responsible for repairing any damage caused by Sublandlord in
connection therewith, and (ii) in the event Subtenant constructs, during the
Term, additional floor(s) on the Building, Sublandlord shall, at Sublandlord's
expense, have the right to relocate the Sublandlord Equipment to the new roof on
the Building, in such place and manner as Sublandlord and Subtenant in good
faith mutually agree (provided that Subtenant shall not be liable to Sublandlord
for any loss, cost, damage or expense incurred in connection with the removal of
such Sublandlord Equipment in connection with any construction on the roof), and
(iii) in the event Subtenant reasonably determines that the Sublandlord
Equipment must be relocated because it unreasonably interferes with the use and
occupancy of the Sublease Premises by Subtenant, Sublandlord shall, at
Sublandlord's expense, relocate such Sublandlord Equipment to a location upon
which Sublandlord and Subtenant in good faith mutually agree, (c) during the
Term, the door in the Non-Sublease Premises which opens into the lobby of the
Building shall remain and be used only as a means


                                       23

of egress from the Non-Sublease Premises during an emergency, and (d) the
elevator located in the Sublease Premises which descends to the basement of
the Building may be used by handicapped employees of the lessee of the
Non-Sublease Premises, on a non-exclusive basis, for the purpose of accessing
the basement of the Building.

                           [SIGNATURES ON NEXT PAGE]


                                       24

         IN WITNESS WHEREOF, Sublandlord and Subtenant have duly executed this
Sublease as of the day and year first written above.

                                          SUBLANDLORD:

                                          325 SPRING STREET LLC,
                                            a Delaware limited liability company

                                          By: 325 Savanna LLC

                                          By:  /s/ ILLEGIBLE
                                              ------------------------------
                                               Name: Illegible
                                               Title: Member

                                          SUBTENANT:

                                          IMCLONE SYSTEMS INCORPORATED

                                          By:  /s/ JOHN B. LANDES
                                              ------------------------------
                                               Name: John B. Landes
                                               Title: Senior Vice President


                                          ILLEGIBLE
                                          ----------------------------------
                                          Subtenant's Tax I.D. #


                                       25

                                   SCHEDULE 1

                                   Fixed Rent

For purposes hereof, "Lease Year" shall mean (i) with respect to Lease Year 1,
the period commencing on the Commencement Date through and including April 30,
2002, and (ii) with respect to each succeeding Lease Year, each period of twelve
(12) months commencing on May 1, and each succeeding May 1 thereafter, and
ending on the day preceding the anniversary thereof (for example, Lease Year 2
is the period from May 1, 2002 through April 30, 2003, Lease Year 3 is the
period from May 1, 2003 through April 30, 2004, etc.).

Lease Year 1:  $  350,000.00  ($50,000.00/mo.)
Lease Year 2:  $  600,000.00  ($50,000.00/mo.)
Lease Year 3:  $2,082,000.00 ($173,500.00/mo.)
Lease Year 4:  $2,085,000.00 ($173,750.00/mo.)
Lease Year 5:  $2,090,000.00 ($174,166.66/mo.)
Lease Year 6:  $2,255,000.00 ($187,916.66/mo.)
Lease Year 7:  $2,275,000.00 ($189,583.33/mo.)
Lease Year 8:  $2,290,000.00 ($190,833.33/mo.)
Lease Year 9:  $2,340,000.00 ($195,000.00/mo.)
Lease Year 10: $2,350,000.00 ($195,833.33/mo.)
Lease Year 11: $2,380,000.00 ($198,333.33/mo.)
Lease Year 12: $2,580,000.00 ($215,000.00/mo.)
Lease Year 13: $2,631,000.00 ($219,250.00/mo.)
Lease Year 14: $2,700,000.00 ($225,000.00/mo.)
Lease Year 15: $2,725,000.00 ($227,083.33/mo.)
Lease Year 16: $2,727,000.00 ($227,250.00/mo.)
Lease Year 17: $2,730,000.00 ($227,500.00/mo.)
Lease Year 18: $2,735,000.00 ($227,916.66/mo.)
Lease Year 19: $2,780,000.00 ($231,666.66/mo.)
Lease Year 20: $2,785,000.00 ($232,083.33/mo.)
Lease Year 21: $2,790,000.00 ($232,500.00/mo.)
Lease Year 22: $2,795,000.00 ($232,916.66/mo.)

                                   SCHEDULE 2

                                Sublease Consent

                              CONSENT TO SUBLEASE

         CONSENT TO SUBLEASE AGREEMENT (this "Consent") made as of October 5,
2001, by and among UNITED PARCEL SERVICE, INC, a New York corporation, having an
office and place of business at 643 West 43rd Street, New York, New York, 10036,
as owner ("Owner"), 325 SPRING STREET LLC, a Delaware limited liability company,
having an office and place of business at, c/o Savanna Partners, 80 Fifth
Avenue, New York, New York 10011 (as assignee of SenseNet, Inc., "Tenant"), as
tenant, under a certain agreement of lease, dated as of May 8, 2000, by and
between Owner and Tenant (as amended by that certain First Amendment of Lease,
dated as of November 1, 2000 and as further amended by that certain Second
Amendment of Lease, dated as of October 4, 2001, the Lease"), pursuant to which
Tenant has leased the certain premises (the "Demised Premises") in the building
(the "Building") known as 325 Spring Street, New York, New York, as more
particularly described in the Lease, and IMCLONE SYSTEMS INCORPORATED, a
Delaware corporation, having an office and place of business at 180 Varick
Street, New York, New York ("Subtenant").

         Pursuant to the terms of a Sublease, dated as of October 5, 2001 (the
"Sublease"), a true and complete copy of which Tenant and Subtenant each
represent is attached hereto as Exhibit A and made a part hereof, Tenant has
subleased to Subtenant a portion of the Demised Premises more particularly
described in Sublease (the "Sublease Space").

         Owner hereby consents to the subletting by Tenant to Subtenant of the
Sublease Space, such consent being subject to and upon the following terms and
conditions, to each of which Owner, Tenant and Subtenant expressly agree:

         1. Except as expressly provided herein to the contrary, nothing herein
or in the Sublease contained shall:

                  (a)      operate as a consent to or approval by Owner of any
                           of the terms, covenants or conditions of the
                           Sublease, and Owner shall not be bound thereby,
                           except as provided herein;

                  (b)      be construed to modify, waive or affect: (i) any of
                           the provisions, covenants or conditions contained in
                           the Lease; (ii) any of Tenant's obligations under the
                           Lease, or to waive any breach thereof, or (iii) any
                           rights of Owner under the Lease (except insofar as
                           they are modified by the provisions of this Consent
                           and/or in connection with the Sublease);

                  (c)      be construed to enlarge or increase Owner's
                           obligations under the Lease, to establish Subtenant
                           as a party entitled to the performance or benefit of
                           any of such obligations, or to confer upon Subtenant
                           any benefits or legal rights under the Lease; or

                  (d)      operate as a consent to or approval by Owner of any
                           alteration, modification, improvement or renovation
                           of the Sublease Space or any part thereof to
                           accommodate Subtenant or otherwise (and Subtenant
                           covenants not to make any alteration, modification,
                           improvement or renovation therein except in
                           accordance with, and subject to, the provisions of
                           the Lease and this Consent).

         2. This consent is not assignable.

         3. In order to induce Owner to execute and deliver this consent, Tenant
agrees to pay or cause to be paid to Owner, as additional rent under the Lease,
an amount equal to One Million Dollars ($1,000,000) in lieu of a share of any
rent and/or other consideration paid by Subtenant to Tenant, and the
effectiveness of this Consent is contingent upon receipt of such funds. Owner
shall acknowledge receipt of such funds as and when received.

         4. The Sublease shall be subject and subordinate at all times to the
Lease and all of the provisions, covenants and conditions thereof. If there
shall be a conflict between the provisions of the Lease and the Sublease, the
provisions of the Lease (as modified by the provisions of this Consent) shall
prevail.

         5. Neither the Sublease nor this consent thereto shall release or
discharge Tenant from any liability under the Lease, and Tenant shall remain
liable and responsible for the full performance and observance of all the
provisions, covenants and conditions set forth in the Lease on the part of
Tenant to be performed and observed. Any breach or violation of any provision of
the Lease by Subtenant shall be deemed to be and shall constitute a default by
Tenant in fulfilling such provision.

         6. Except as expressly provided in Paragraph 8 hereof or the Lease to
the contrary (i) this consent by Owner shall not be construed as a consent by
Owner to any further subletting either by Tenant or Subtenant and (ii) the
Sublease may not be assigned, amended, modified, renewed or extended, nor shall
the Demised Premises, or any part thereof, be further sublet, used by others or
licensed as desk space, without the prior written consent of Owner in each
instance. Any violation of the provisions of the immediately preceding sentence
by Tenant or Subtenant shall be a default under the Lease. Subtenant shall
procure all insurance coverage contemplated by the Lease and the Sublease and
shall include Owner and Owner's managing agent for the Building, if applicable,
as additional insureds thereunder.

         7. Except as otherwise specifically provided below in this Consent,
upon the expiration or any earlier termination of the term of the Lease, or in
case of the surrender of the Lease by Tenant to Owner, the Sublease and its term
shall expire and come to an end as of the effective date of such expiration or
termination, and Subtenant shall vacate the Sublease Space on or before such
date. Notwithstanding the foregoing, if the Lease shall expire or terminate
during the term of the Sublease for any reason (including any recapture by
Owner) other than (A) condemnation or destruction by fire or other casualty
(subject to Section 10(d) of the Lease, (B) as a result of any default or breach
by Subtenant of the terms of the Sublease, the Lease or this Consent beyond any
applicable notice and cure period, or (C) both Tenant and Subtenant voluntarily
surrendering the Lease and Sublease to Owner during the term of the Sublease,
then without any additional or further agreement of any kind on the part of
Owner or Subtenant, effective as of such expiration or termination date and
notwithstanding such fact, Subtenant's occupancy rights under the Sublease shall
continue with the same force and effect as if Owner, as lessor, and Subtenant,
as lessee, had entered into a direct lease as of such effective date for a term
equal to the then unexpired term of the Sublease but containing all of the same
provisions as those contained in the Lease, including the Base Rent due
thereunder (except to the extent any provision thereof is in conflict with the
provisions of this Paragraph 7 or Paragraph 8 of this Consent, in which case,
the provisions of this Consent shall prevail), in which event Subtenant shall
attorn to Owner and Owner and Subtenant shall have the same rights, obligations
and remedies thereunder as were had by Tenant thereunder prior to such effective
date, except that in no event shall Owner be: (i) liable for any act or omission
by Tenant; (ii) subject to any offsets or defenses which Subtenant had or might
have against Tenant; (iii) bound by any payment of rent, additional rent or
other sum made by Subtenant to Tenant in advance of any periods reserved
therefor in the Sublease except for the prepayment by Tenant of the first
month's Base Rent ($57,375.00); (iv) required to make any installation or do any
alteration or work for Subtenant; or (v) liable for the return of any security
deposit made by Tenant or liable for the return of any


                                       -2-

security deposit made by Subtenant not actually received by Owner. In such event
each of Subtenant and Owner agree to execute such agreement as the other party
shall reasonably request to evidence the foregoing direct Lease and the terms of
Paragraphs 7 and 8 hereof. Upon any expiration or termination of the Sublease
pursuant to the provisions of the first sentence of this Paragraph 7, in the
event of the failure of Subtenant to vacate the Sublease Space as herein
provided, Owner shall be entitled to all of the rights and remedies available to
a landlord against a tenant holding over after the expiration of a term and to
all losses and damages, direct or consequential, and all reasonable attorneys'
fees, incurred or suffered by Owner by reason thereof.

                  8. Notwithstanding anything to the contrary contained in this
Consent or the Lease, each of Owner, Tenant and Subtenant acknowledges and
agrees that:

                  (i) Subtenant shall be permitted to use the Sublease Space for
the "Permitted Use" as defined in Section 3 of the Sublease,

                  (ii) the terms and provisions, and rights and obligations, set
forth in Section 22 of the Lease, including the right to obtain a
Non-Disturbance Agreement (as defined in the Lease), shall inure to the benefit
of, and be binding upon, Subtenant, as if Subtenant were the "Tenant" first
named in the Lease,

                  (iii) the terms and provisions set forth in Section 23 of the
Lease shall inure to the benefit of, and be binding upon, Subtenant, as if
Subtenant were the "Tenant" first named in the Lease, and for purposes hereof
any reference therein to Dane Atkinson and/or Bernar Bekirov shall be deemed
deleted,

                  (iv) Owner hereby consents to (A) the use of the Atrium Area
as a permanently enclosed area and/or as additional office space and (B)
Subtenant's HVAC Rights (as defined in Section 18C of the Sublease); provided
that, any Alterations to or effecting the Atrium Area, or the roof or other
structural or exterior components of the Building, shall remain subject to all
of the remaining provisions of Section 6 of the Lease or any other provisions of
the Lease applicable to Alterations or to Tenant's use and occupancy of the
Demised Premises, including all required approvals and consents and, provided,
however, that nothing herein or in Section 6(d) the Lease is intended or shall
be deemed to require Tenant or Subtenant to remove (x) any Alterations performed
or installed in connection with Subtenant's HVAC Rights, except to the extent
that removal thereof is an express condition to Owner's consent or approval
thereof at the time same is granted, or (y) any structural or exterior
components of the Alterations, including any new roof or enclosure, performed or
installed in connection with the construction of the Atrium Area; and provided
further that, for purposes of Section 6(d) of the Lease, any "clean rooms",
walk-in refrigeration or cooling units or other built-in laboratory equipment
that is not readily convertible to general office use or would otherwise
materially increase demolition or reletting costs incurred by Owner shall be
deemed "specialt" installations under the Lease; and except as modified herein,
all of the terms. of Article 6 of the Lease shall inure to the benefit of, and
be binding upon, Subtenant, as if Subtenant were the "Tenant" first named in the
Lease.

                  (v) Tenant shall have the right to grant a leasehold mortgage
secured by Tenant's interest in the Demised Premises to Subtenant (or any
Affiliate of Subtenant created or existing for the purpose of making such
mortgage loan), and

         (vi) the terms and provisions set forth in Section 18 of the Lease
shall inure to the benefit of, and be binding upon, Subtenant, as if Subtenant
were the "Tenant" first named in the Lease; provided, however, that Section
18(b) of the Lease shall not be applicable thereto.


                                      -3-

         9. Tenant shall be and continue to be liable for all bills rendered by
Owner for charges incurred by or imposed upon Subtenant for services rendered
and materials supplied to the Demised Premises, and both Tenant and Subtenant
shall be and continue to be liable for all bills rendered by Owner for charges
incurred by or imposed upon Subtenant for services rendered and materials
supplied to the Sublease Space. Owner may submit bills to Subtenant directly for
all such charges related to the Sublease Space, but neither such billing nor
Owner's acceptance of payment directly from Subtenant shall create or be deemed
to create any privity of contract between Owner and Subtenant, it being
understood and agreed that Owner's transmittal of bills to Subtenant and
acceptance of payment from Subtenant will be done solely to accommodate Tenant.

         10. Tenant hereby agrees to indemnify and hold Owner harmless with
respect to all liability, costs and expenses incurred by Owner in connection
with any action or proceeding brought by Subtenant (or parties claiming through
Subtenant) against Owner to enforce the obligations of Owner under the Lease.
Unless and to the extent that Subtenant shall become a direct tenant of Owner
pursuant to Paragraph 7 above, notwithstanding anything in the Sublease to the
contrary, (i) neither Subtenant nor any parties claiming through Subtenant shall
have or be deemed to have any privity with Owner, it being agreed by Subtenant
that any rights it may have in respect of the Sublease Space derive solely from
Tenant and (ii) in no event shall Owner be liable to Subtenant (or parties
claiming through Subtenant) for Owner's failure, if any, fully to perform and
observe all of the provisions, covenants and conditions set forth in the Lease
on the part of Owner to be performed and observed.

         11. Any notice or communication which Tenant or Subtenant may desire or
be required to give to any other party under or with respect to this consent
shall be given in the fashion provided in the Lease.

         12. Each of the following shall constitute a default by Tenant under
the Lease: (a) any extension of the term of the Sublease without the prior
written consent of Owner; (b) any modification or amendment of the Sublease
without prior written consent of Owner; or (c) any failure by Tenant or
Subtenant to comply with the terms and provisions of this Consent. If any one or
more of the foregoing defaults occurs Owner shall be entitled to enforce any or
all of its remedies under the Lease, at law or in equity.

         13. Tenant and Subtenant hereby jointly and severally represent and
warrant to and for the benefit of Owner that, except as is expressly set forth
and described in the Sublease, Subtenant has not paid, is not paying, and has
not obligated itself to pay (conditionally or otherwise) any rent, additional
rent or other consideration of any type or nature whatsoever for or in respect
of the Demised Premises, the Sublease or any other thing or matter in connection
with or related to any of the foregoing, except for Subtenant's contribution
toward the payment of the sum described in Paragraph 3 hereof and the mortgage
loan consented to in Paragraph 8 hereof.

         14. Subtenant shall not use the words UPS or UNTED PARCEL SERVICE in
any advertising or for any other promotional or profit making purpose whatsoever
and any sublease of all or any part of the Demised Premises or any assignment of
the Sublease shall contain a provision identical to this paragraph.

         15. Subtenant hereby confirms receipt of notification from Owner that,
the Building may be located on, or hereafter may be deemed, a landmark site or
otherwise subject to Title 25, Chapter 3 of the Administrative Code of the City
of New York (the "Landmarks Law") and, in such event, in accordance with
Sections 305, 306, 309 or 310 of the Landmarks Law any occupant of the Demised
Premises must obtain a permit from the Landmarks Preservation Commission of the
City of New York before commencing any exterior or interior work in or to


                                       -4-

the Demised Premises, except for ordinary repair and maintenance as that term is
defined in Subdivision (r) of Section 302 of the Landmarks Law.

         16. This Consent, which shall be construed in accordance with the
internal laws of the State of New York without regard to principles of conflicts
of law, contains the entire agreement of the parties hereto with respect to the
subject matter hereof and may not be changed or terminated orally or by course
of conduct. All prior understandings and agreements with respect to the subject
matter hereof are merged into this Consent, the Lease and the Sublease which
alone reflect the agreement of the parties hereto. This consent shall be void
and of no force and effect until executed by Owner and unconditionally delivered
to Tenant.

         17. This consent may be executed in any number of counterparts, each of
which (together or separately) shall be an original, but all of which shall
constitute one instrument.


                                       -5-

         IN WITNESS WHEREOF, the parties hereto have duly executed this Consent
To Sublease Agreement as of the day and year first above written.

                                                Owner:

                                                UNITED PARCEL SERVICE, INC.,

                                                By:_____________________________
                                                Name: _________________
                                                Title:_________________

                                                Tenant:

                                                325 SPRING STREET LLC,

                                                By: 325 Savanna LLC

                                                By:_____________________________
                                                Name:
                                                Title:

                                                Subtenant:

                                                IMCLONE SYSTEMS INCORPORATED

                                                By:_____________________________
                                                Name:
                                                Title:


                                      -6-

                                   SCHEDULE 3

                               Landlord Estoppel

                              LANDLORD'S ESTOPPEL


                                                October   , 2001


325 Spring Street
c/o Savanna Partners
80 Fifth Avenue
New York, New York 10011

ImClone Systems Incorporated
180 Varick Street
New York, New York 10014

                  Re:      Lease Agreement, dated as of May 8, 2000, by and
                           between United Parcel Service, Inc., as Landlord, and
                           Sensenet, Inc. ("Sensenet"), as Tenant, as (i)
                           amended by that certain First Amendment to Lease
                           Agreement, dated as of November 1, 2000 and that
                           certain Second Amendment to Lease, dated as of
                           October 4, 2001, and (ii) assigned pursuant to that
                           certain Assignment and Assumption of Lease, dated as
                           of November 1, 2000, by and between Sensenet,, as
                           Assignor, and 325 Spring Street LLC ("325"), as
                           Assignee (collectively, the "Lease")

Gentlemen:

         In connection with that certain Sublease ("Sublease"), by and between
325, as Sublandlord, and ImClone Systems Incorporated ("ImClone"), as Subtenant,
dated as of the date hereof, a copy of which is annexed hereto as Exhibit A,
Landlord hereby certifies to 325 and ImClone as follows:

         1. To the best knowledge of Landlord, 325 is not in default in the
performance of any covenant, agreement or condition contained in the Lease,
Landlord has not delivered to 325 any notice of default under the Lease that
remains uncured and to the best knowledge of Landlord, no event has occurred
which, with the passage of time or the giving of notice, or both, would
constitute a default by 325 under the Lease.

         2. Landlord is not in default in the performance of any of its
obligations under the Lease, nor, to the best knowledge of Landlord, has any
event occurred which, with the giving of notice or passage of time, or both,
would constitute a default by Landlord under the Lease. Landlord has not yet
received any notice of default under the Lease.

         3. The Lease (together with any amendments thereto), a copy of which is
attached hereto as Exhibit "B" is in full force and effect and constitutes the
entire agreement between Landlord and Tenant with respect to the Premises and
has not been modified except as described in any amendments attached hereto.

         4. No work is required under the Lease to have been done to date by
Landlord. Landlord has no right to "buyback" the Lease or "buy out" 325's
interest in the Lease.

         5. Landlord hereby acknowledges that it has heretofore received
$57,375.00 on account of Base Rent (as defined in the Lease) payable under the
Lease for the month of May, 2003.

         The foregoing statements are not affirmative representations,
warranties or covenants nor shall they shall they subject Landlord to any
liability whatsoever, the sole effect of same being to estop Landlord from
making assertions to the contrary of such statements against 325 or ImClone.
Landlord acknowledges that this certificate and consent will be relied upon only
by 325 and ImClone in connection with consummation of the Sublease and that it
is solely for the benefit of 325 and ImClone in connection with the Sublease and
may not be relied upon by any other person or for any other purpose whatsoever.

         The person executing this certificate is duly authorized and empowered
to do so.

                                                Very truly yours,

                                                UNITED PARCEL SERVICE


                                                By:_____________________________
                                                   Name:
                                                   Title:


                                      -2-

                                    EXHIBIT A


                                    Sublease


                                      -3-

                                   EXHIBIT B

                                     Lease


                                      -4-

                                   EXHIBIT A

                               Sublease Premises

                                   EXHIBIT B

                                 The Overlease